


1000 Word - Smut Anthology (Undertail)

by Dark_Crystal_Demon



Category: Undertale (Video Game)
Genre: - kinda, Biting, Chapter 1 -, Chapter 2 -, Dadster, Light Bondage, Master/Pet, Master/Servant, Other, Possessive Behavior, Threesome - F/M/M, Voyeurism, Wax Play, role play
Language: English
Status: In-Progress
Published: 2017-05-21
Updated: 2017-05-22
Packaged: 2018-11-03 09:11:50
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,340
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10964175
Author URL: https://archiveofourown.org/users/Dark_Crystal_Demon/pseuds/Dark_Crystal_Demon
Summary: 1000 word ficlets of smut from all over the Undertail verse and alternative universes.Each chapter is it's own story. The title has the pairing. The beginning notes in each chapter have any additional warnings for the story.I hope you enjoy these little ficlets of smut.





	1. Birthday Punishment (Dadster!Gaster x Fem!Reader)

**Summary for the Chapter:**

> Gaster takes you out for your birthday, but later has to punish you for your actions... not too much though. It is your birthday ;) 
> 
> Warning:  
> Master/Pet Play
> 
> Commission for Anonymous.

Gaster has taken you and his sons to Mettaton's dance club. Not because he enjoys such things. Loud music, sweaty monsters, and irresponsible drinking are not to his tastes, but they are yours. And it's your birthday. Your master is feeling generous tonight. 

His purple collar around your neck, you dance as he watches from a secluded booth in the darkest corner of the club. You search for his face behind the flashing lights and gyrating bodies, but Papyrus blocks your view. He's more energetic than usual. You've noticed he's been accepting every drink Sans gives him as a challenge. "THIS MUSIC RATTLES MY BONES!"

You smile and wonder if skeletons can get hangovers. Then the beat drops, the bass blasts through the crowd, and you lose yourself to it. 

"HUMAN, I DIDN'T KNOW YOUR BODY COULD BEND THAT FAR!"

"i did," a deep whisper in your ear startles you as bony fingers grip your waist and move your ass against his leg. 

"SANS! I'M GLAD YOU FINALLY DECIDED TO DANCE WITH US! BUT YOU'RE HINDERING HER MOVEMENTS!" 

"am i? sorry, pet," the alcohol on Sans' breath is strong. It had to be for him to call you by that nickname. That is his father's name for you... and where is Gaster? You feel gravity pull around you, bringing Papyrus against your front.

"SANS WHAT ARE YOU -? OH HUMAN, YOU ARE VERY SOFT!" Papyrus hasn't stopped moving to the music. His hips grind against yours and push you back harder against San's leg. The sensation of being trapped between their bodies is a sensory overload. Papyrus gets lost in the feeling of your body against his. His chest presses against yours. His hands grip your shoulders. 

You reach up to push him away, but Sans is faster. His hands snatch yours from the air and pull them behind you. He traps your hands against his waist as his brother pushes you further against him. 

"not sure why you prefer the ol' man," Sans pulls your hands down further until you have to grip his hips for balance. You blush as you feel more than bones from both of the brothers... Sans juts his knee further up between your legs. "mmm... what a warm welcome you have for me."

He bites your ear lobe as he pulls your hands to his ass. "i think you're ready for a new master..."

Then the world goes black. The music is replaced with the silent rush of a dark wind that pushes the two skeletons away from you and wraps around your body. You close your eyes as the void cools your flushed skin and calms your beating heart. Master...

When you open your eyes, you're back home. Gaster's arms keep you pinned against him as Sans and Papyrus sprawl on the ground. Papyrus quickly kneels, apologizing. (I'M SORRY, DAD! SHE IS SOFT! AND THE MUSIC...) Sans remains quiet. His eyes stay on you as he slowly picks himself up to his feet and dusts off the shoulders of his blue jacket. You blush at the desire he's still prominently displaying in his pants...

" **Go to your rooms** ," Gaster growls, his grip bruising your waist. " **I'll deliver your punishment in the morning.** "

Papyrus obediently races up the stairs, but Sans follows at a decidedly slower pace. Gaster's fingers begin to dig painful trails down to your hips and up to your chest. You let out a small whimper for his enjoyment as his head dips to the ear Sans had just been whispering in, " **My little birthday slut needs to be punished.** "

His snarl smells of whiskey and cigar smoke. He pulls up your skirt with one hand and slips the other under your shirt, tweaking your nipple hard. You gasp, head falling back against his shoulder as he bites your neck.

Your eyes catch movement above you. You realize Sans hasn't gone into his room yet. Instead, he's watching you from the top of the stairs. " **My pet.** "

You turn away from Sans' gaze and nuzzle your head against Gaster's scarred skull, "Yes, Master. I'm yours."

The world turns dark again as you fall into a straddle around his waist. He sits upright on his bed.

Facing him for the first time since the evening began, you're relieved to see the mischievous glint in his eye lights. Music starts to play, but it's not the digital remixes of the club; instead, it's a melodic jazz tune, one you've heard countless times. 

Somewhere in the lastest void jump, you lost your underwear and his pants came unzipped. He rises between you, his tip slipping under your shirt and caressing your belly button. He has made himself longer tonight to punish you. " **Dance for me, pet.** " 

His dark smile says the rest: he's provided a pole for you to dance on.

"Yes, Master." You return his grin and rise yourself just above his penis.

"You're already so wet, slut," he growls, his hand knotting in your hair and yanking your head back. You yell out as he directs your body down around his cock. " **That's right, pet. Louder. I want them to hear you.** "

You comply, moaning up to the ceiling where their rooms are, as you accommodate his whole length inside you. " **Dance.** "

Balancing yourself on his broad thick shoulder bones, you find a rhythm.

His cock stiff inside you, his own moans muffled against your neck, you start to pick up speed. He bites your skin in approval.

"Oh, Master," It's difficult to get the words out between your breaths. He thrusts pushing further inside as your pace quickens. You nearly scream, but you don't care anymore. He's so deep...

You cum in a flurry of thrusts that squeeze him until he also cums inside you. His warm magic fills you while you fall against his chest. 

" **Maybe we should make them a sibling. That should remind them who you belong to,** " Gaster whispers into a soft chuckle as your back stiffens. Your mind immediately thinks of the cum dripping between your legs. He pets the tension out of your spine, and kisses the top of your head. " **Not yet, pet. But soon, I'll make you beg for it.** "

**Notes for the Chapter:**

> Mmmm... possessive dadster. What did you think? 
> 
> If you'd like to get updates about what latest projects I'm working on, you can always go to my [Tumblr](https://www.tumblr.com/blog/darkcrystaldemon). I also reblog a shameless amount of smutty undertail pieces.


	2. Paying The Tab (Sans x Fem!Reader x Grillby)

**Summary for the Chapter:**

> You help Sans pay his tab at Grillby's.
> 
> Warning:  
> Master/Servant  
> Light Bondage  
> Fire Kink
> 
> Smut Raffle Winner: mikrebyle.

**Notes for the Chapter:**

> Not gonna lie, I went a little off script on this one and pushed it past 1000, but it's still below 1500, so I think it still counts?

When Sans said you were about to meet an old flame of his, you should have realized he was also making a pun. He tells you Grillby is still a very good friend, and just opened his own bar downtown in the monster quadrant of the city.

"i thought we could check it out," he shrugs as you get closer to the building. It's wooden exterior complements the park you're both walking out from. You'd just finished the hiking trail up the mountain. Gazing at the stars, you'd lost track of time and now your stomach grumbled. You needed food, but this place... 

"You just trying to show me off to your ex-boyfriend?" 

"nah, but don't act like you don't like being put on display," Sans grabs your ass just as some monsters bike by on the trail. One of the bikers shakes their head, but you don't stop Sans' hand from exploring further. "not even wearing any underwear. you kinky minx. you and grillz will get along just fine."

You hoped he was right, or this was going to be an awkward dinner.

When you walked in the bar, you both eyed each other as two people do when they know they've shared the same lover. You had to admit, Grillby was gorgeous, a sculpted frame of a man made of fire, a controlled inferno that threatened to burn his entire establishment down... or just turn you to ash as his lips kissed the back of your hand in greeting. 

You flushed under his warmth, but soon regained your composure. You sampled mini burgers that Sans dosed in ketchup, and you both exchanged magical shots and stories of the comical skeleton who sat grinning between you. 

After a few drinks and a warm buzz in your gut, you started sharing kinkier tales. 

You raise you skirt for Grillby to see the tiny dots of petechiae that trail along your thigh from your latest rope adventures. Grillby reaches across Sans' lap to trace his fingers over your skin. He nearly burns you with his touch, and you let out a tiny gasp. Grillby's grip tightens, for a moment, at your reaction before he lets go. Your skin is red and flushed where he removes it. 

"watch out, my little rope bunny. grillz can't control his heat if you tease him like that," Sans chuckles, but his arm sneaks behind your waist protectively at the same time.

"I apologize for my temperature fluctuation," Grillby's voice has a deep timbre that crackles like a campfire under the night sky. 

He's mesmerizing. You blush, shaking your head even as Sans' grip tightens around your waist. "There's nothing to apologize for." Your finger traces the edges of the burn mark enjoying the bite of its heat on you skin. Like a sunburn, it would probably last for a week. "I always enjoy a little fire play." 

Your eyes lock onto Grillby's as he sits more upright on his stool. He raises his brow, a small smirk curling up along the corner of his fiery lips, "Indeed?"

You lick your lips, nodding your head as the last of the patrons leave the bar. They place their money on the table rather than try to interrupt the exchange between you. Sans moves to get off his stool. "well, it's about time for us to leave, eh?"

"Or," Grillby's voice is nearly a purr as his hand falls on Sans' thigh. "It's about time you pay your tab."

"her tab ain't that high."

"Do you really think she'll mind?"

And that's how you found yourself going behind the bar to Grillby's home. A stark contrast to the wooden business in the front, you were now greeted with stone walls, furniture and... a dungeon kinkier and more equipped than any you've ever seen in your lifetime. 

"Strip," Grillby's voice became forceful.

"Yes... Master," you reply with only a moments hesitation. The men had explained the terms to you at the bar: role play with Grillby directing the scene. You have to admit, your heart is racing in anticipation. It had been a long time since you'd done anything with more than one partner.  

As you both undressed, Sans takes you in his arms and kisses you hard against your lips. "you're the sexiest woman alive for doing this." The bones of his body press into your skin, his tongue darting into your mouth as his hands pull your hips into him. 

"My, my, you are an attractive couple," Grillby chuckles. The heat in the room picks up as he burns the clothes off his own body and reveals an impressive erection. He sits himself down on a chain swing, cock in hand. "Now take your woman to the table and tie her up. That burn on her thigh won't allow for suspension this time."

 _This time_... how big is Sans' tab?

Under Grillby's direction, Sans ties your hands and feet to the four corners of the table. Not too tight, but your legs are spread far wider than usual, stretching your flexibility. "Now crawl on top of her and wiggle that bony ass."

Sans obeys, stealing a kiss while his hips sway above you, rubbing his erection over your stomach. You moan at the feeling. 

"I like her noises, I bet she gets louder when she's bitten?"

Sans smiles into his kiss and bites your lip. You moan louder. He trails kisses and bites along your neck. But you moan the loudest as you feel fiery kisses along your calf as well. Flames biting into your skin. You thought he was only going to observe, but you can't hide the arousal at being kissed by two incredibly sexy monsters.

"Enter her."

Sans obeys, lifting your hips to slide his girthy member inside you. He stretches your walls as he fills you with his magic dick. You feel both their eyes on your face as your lips form an O as Sans hilts himself entirely inside you. He's just so big.

Beside the table, Grillby begins directing his rhythm and watching your reactions carefully. You revel at their attention, the small caresses that begin to get more forceful as you feel your first orgasm coiling inside you.

But then Grillby loses his control and crawls on the table. You feel your lover stiffen inside you as Grillby bends him further on top of you and enters inside his pelvic bone.

Sans' bones heat up against your skin, but their magic absorbs most of Grillby's fire. His thrusts inside you become extensions of Grillby's own inside him. You marvel as both men thrust between your legs. The view of Sans' face as he's being penetrated is pushing you over the edge while his cock grows inside you with increased magical desire. 

You scream in orgasm, but both men are lost to their rhythm and not stopping. You ride their thrusts with your own insatiable need to cum again... and you do, again and again, amidst the grunts and groans above you. You pull at your restraints, but you can't escape them. You can barely breathe. 

Finally Sans takes mercy, "master, may i cum?"

"You may," Grillby answers with a powerful thrust of his own that ejects orange flames of magic inside Sans' skeleton. They drip from his bones like hot wax onto your skin and you moan as Sans also finishes himself inside you. The wax bringing you to orgasm with him. Grillby remains inside Sans and enjoying the scene the below him.

As Sans collapses on top of you, Grillby pulls himself out and releases you from your restraints, while planting small kisses on your wrists and ankles. He pats the back of Sans skull as he kisses your cheek, "thank you." 

Then he leaves the room for you both to clean up.

**Notes for the Chapter:**

> So Grillby originally wasn't supposed to join in... but I just really liked the image... let me know what you thought about it. 
> 
> If you want to keep up with my latest projects or look at a lot of smutty reblogs, check out my [Tumblr](https://www.tumblr.com/blog/darkcrystaldemon).


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